The technical field of this invention is material analysis and, in particular, the invention relates to the detection and quantification of analytes in materials by measuring the absorption of near infrared light.
Material analysis, especially the analysis of liquid materials for the presence of solutes, can be a tedious and complex task. In many instances, it would be more desirable to be able to analyze materials quickly, easily and non-invasively. One example of such an application is blood analysis.
Treatment of many medical disorders, such as diabetes and other hormonal or metabolic disorders, requires accurate blood analysis. Additionally, in some situations, repeated or even continuous blood monitoring is desirable, for example, when monitoring drug dosage changes or variations in metabolic factors, such as glucose or cholesterol.
Conventionally, blood is analyzed by withdrawing a sample from the body of a subject and examining it, using one or more techniques, such as immunoassays, activity assays, chromatographic assays and spectrophotometric assays. These conventional methods suffer from several common disadvantages. One such disadvantage is that these tests are invasive and raise the risk of patient infection and discomfort. Also, such tests can be time-consuming. This time delay between when the blood is drawn and when the analysis is completed provides a window during which the subject's blood content may have changed, possibly leading to erroneous test results. A further disadvantage to conventional blood testing techniques is that the people drawing and testing the blood sample are put at risk for exposure to infectious disease agents.
Accordingly, it is the object of the present invention to provide an analytic apparatus for non-invasively, quickly and continuously detecting and quantifying analytes in a blood sample.
It is another object of this invention to provide a method and apparatus for non-invasive detection of blood-glucose levels but which avoids the problems of non-continuous test results, subject discomfort and potential technician exposure to infectious agents.